ChemBench

Activation Energy Calculator

Extract Ea from two experimental data points.

The two-point form of the Arrhenius equation

Measuring a reaction's rate constant at two different temperatures lets you solve directly for activation energy, without ever needing to know the pre-exponential factor A.

A standard lab technique

This two-temperature method is exactly how activation energies are measured experimentally — run the same reaction at two temperatures, time it, and solve for Ea from the rate constants.

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ChemBench

Activation Energy Calculator

Extract Ea from two experimental data points.

Rate constant k₁

Temperature T₁ (K)

Rate constant k₂

Temperature T₂ (K)

Activation energy

91,889.724 J/mol

What you entered

Rate constant k₁: 0.001Temperature T₁ (K): 300Rate constant k₂: 0.01Temperature T₂ (K): 320

1
ln(k₂ ÷ k₁)
ln(0.01 ÷ 0.001)= 2.3026
2
Ea = −R × ln(k₂/k₁) ÷ (1/T₂ − 1/T₁)
−8.314 × 2.3026 ÷ (1/320 − 1/300)= 91889.7238 J/mol

Result

Activation energy: 91,889.724 J/mol

The reaction's activation energy is 91,889.724 J/mol.

The two-point form of the Arrhenius equation

Measuring a reaction's rate constant at two different temperatures lets you solve directly for activation energy, without ever needing to know the pre-exponential factor A.

A standard lab technique

This two-temperature method is exactly how activation energies are measured experimentally — run the same reaction at two temperatures, time it, and solve for Ea from the rate constants.